Abrasive wheel



Dec. s, 1942. B. H. WORK ETAL 2,304,226

ABRASIVE WHEEL Filed March Al, 1941 www Fig.

Boyd H VV/K Y David K/aude Jr.- INVENTORS KBY.

lATTORNEY n Patented Dec. 8, 1942 Boyd H'. wor'k ABRASIYE WHEEL and David S. Klander, Jr., Niagara Falls, N. Y., assignors to The Carborundum Co., Niagara Falls, N. Y., a corporation of Delaware Application Maren 1, 1941, seriaiNo. 381,300

.4 Claims.

This invention concerns a resiliently mounted abrasive wheel wherein a resilient bushing is not only an integral part of the wheel but also possesses a predetermined degree o f resilience. An additional feature of this abrasive wheel with an integral resilient bushing of controlled elasticity is the metal sleeve for precision engagement with the spindle of the grinding machine.

The advantages reflected in abrasive wheel performance when the wheel is mounted on a grinding machine' by means of a resilient bushing member are known and recognized in certain classications of grinding operations. -It is generally admitted that greatest benet occurs when grinding with portable machines where the grinder and Wheel are applied as a unitI to the work. Some of these benefits are: greater production from a given wheel, in some instances more metal removed per unit of wheel, longer machine life, less machine maintenance expense, less liability of wheel breakage by reason of mechanical shock, and greater production per labor unit because of less vfatigue to the machine operator. All these benefits are recognized as a direct result of the reduction of the amplitude of vibration of the abrasive wheel and grinding machine when resilient bushings are used, and particularly when used in conjunction with resilient`washers between the sides of the wheel and the fiangesused to secure the wheel in position on the spindle of the grinding machine.

Other types of grinding operations, commonly known in the abrasive industry as snagging and oli-hand grinding, likewise may show better performance when the wheels are provided with resilient bushings. v i

A further advantage of our metal clad resilient bushing lies in thefact that a grinding wheel equipped with it can be removed from one machine and replaced on that, or on another machine without material damage to the metal or rigid bushing member which is the part in direct contact with the grinding machine spindle, as has been stated above and as will be more fully described hereinafter. It is common practice for In the various types of grinding operations, wheels of many sizes are used. For optimum results the resiliency provided must be commensuture.

Resiliency of our bushingcan be controlled by the kind of material used, by the treatment to which some of those materials are subjected,tand by mechanical means.

When our resiliently bushed wheel is mounted with and driven by side anges, resilient washers usually are vemployed between said anges and the wheel in order that the benets of fully resilient mounting of the wheel may be obtained. By combining any desired possible resiliency of the bushing with any desired possible resiliency" of the Washers resulting modication of grinding wheel action can be governed accurately within a Wide range of possible variation.

Resiliency of the washers can be governed by the kind of material employed, by the treatment accorded some of these materials during manufacture and by the thickness of the washers. For

. illustration we choose to use rubber washers.

users of abrasive wheels to change a wheel, after l its diameter has been reduced a certain amount by Wear, to a smaller, or diierent machine. Often times more than one such change is made. As

many remountings as desired can be made Without affecting the precision of our resilient bushing and; consequently without alteration or loss of concentricit'y of wheel and spindle, a very important factor eration.v Y l in safe and satisfactory wheel 0p- Their resiliency can be of any order of magnitude' between that of soft rubber and that of hard rubber. An additional modification of the vinherent resiliency of the washer material that is ultimately imparted to the resiliently bushed Wheel is obtained by means of different thicknesses of the washers. For a given kind of material, for instance what is commonly and broadly known as soft rubber, the thicker the washer the greater will be the magnitude of resilience, or elasticity, imparted to the wheel'.

For a clear understanding of the present invention reference is made to the accompanying drawing, in which:

Figure 1 shows in perspective cross-section an abrasive wheel made with a resilient mounting in accordance with the present invention and ready for'attachment to a grinding machine.

Figure 2 shows in cross-section an abrasive Wheel such as that shown in Figure 1,`but in process of being equipped with its resilient bushing whereby its degree of'resiliency is controlled.

Figure 3 is a side face view kof the wheel shown shows an abrasive wheel I containing an arbor hole 2, of a diameter suitable to the machinevupon which it is to be mounted and fitted with a resilient rubber sleeve 3 positioned in the arbor hole, which sleeve is caused to be under predetermined pressure by metal sleeve 4. The inside diameter of the metal sleeve, or complete bushing, can be made easily to conform with tolerance specifications of the trade. The length of the bushing is made somewhat less than the width of the Wheel to accommodate slight variations in wheel width, as illustrated in the sketch. This leaves small air spaces lat each end of the wheel arbor when mounted, thereby allowing the necessary space for the resilient sleeve or .bushing to yield when subjected to sudden shock. We have also shown rubber washers 6 in position on the sides of the wheel although the clamping means for holding these washers in place are not shown as they are Well known'and familiar to the trade. The use of rubber and other resilient material for washers has long been known. Washers of varying degrees of resiliency can be used to modify the action of our resiliently bushed wheel if desired.

1n Figure 2, we have illustrated diagrammatically one method of assembling the resilient bushing and controlling its degree of resiliency. Abrasive wheel I is provided with arbor hole 2 by any one of several well known methods. sleeve 3 is then inserted. The outside diameter of the rubber sleeve is such that it ts the arbor hole of the wheel but can be placed in position easily. Providing identical resilient material is used, the degree of final resiliency will be determined by the thickness 5 of the rubber sleeve before it has been compressed by the rigid confining sleeve 4, because that thickness determines the magnitude of the compressive stress set up by insertion of the relatively rigid metal sleeve 4. For a given arbor size and metal sleeve, the greater the thickness of the resilient material. the greater will be the compression stress and consequently the less the elasticity of the assembled bushing.` The length of the resilient bushing member 3 is preferably slightly less than the width `of the abrasive wheel, leaving open spaces 1 at each end of the resilient bushing when mounted. Provision is thereby maNde for the rubber or other resilient material of the bushing better to yield when subjected to strong impact shocks in use. The inside surface of the rubber sleeve may be bevelled to facilitate insertion of themetal sleeve. A suitable tool, or fixture, is provided to enlarge the inside diameter of the rubber member and insert the metal member 4 in one operation. At the completion of this simple operation, the bushing, composed of the elastic member and the rigid member, is firmly seated in the arbor hole of the wheel, and has become an integral part of the wheel.

A suitable tool for insertion of the rigid sleeve 4 may be such as that pictured in Figure 2, consisting of an inserting member 9 and a backing member I0. The backing member I-IIis placed against the end of the resilient bushing member opposite the side of insertion to prevent shoving the resilient material out of position, and is provided with projecting portions I I which lit in the arbor hole so that the resilient bushing is not forced Rubber to the extreme face of the wheel. The inserting tool is provided with a tapered portion I2 for spreading and compressing the rubber bushing 3 for reception of the metal sleeve 4 and a recessed portion I3 in which the metal sleeve is placed for insertion. The shoulders I4 permit the insertion of the metal sleeve slightly beyond the side face of the wheel. .The inserting tool is also in two pieces so as tobe easily'withdrawn following insertion of the sleeve.

Figure 3 is a side view illustrating the complete wheel with its integral resilient-bushing unit. Arbor hole 2 of abrasive wheel 'I is tted `with resilient sleeve 3 under predetermined compression provided and maintained by metal sleeve 4. the inside diameter of which metal sleeve has been made to precisely fit, within the usual tolerances, the spindle of the grinding machine., Re-

silient washer 6 is also illustrated, with the understanding that its use is optional. The clamping means for holding the resilient washer in place are not shown.

Figure 4 is a cross-sectional view illustrating a modification of the resilient bushing wherein both ends of the rigid inner sleeve have been belled, or expanded, toform a flange 5 which partially, but not completely confines the open ends of the resilient, or rubber, member. We may use this form of metal member for large, heavy wheels and for wheels that may' have to be remounted many times, to facilitate the mounting and remounting operations. We may also use it when the compressive stresses in the resilient member are low in order to prevent possible slippage of the metal member with respect to the rubber' member during mounting of the wheel on the grinder.

The particular modification of the invention set forth in the drawing shows the resilient bushing slightly less in length than the width of the wheel, leaving air spaces 1 at each end of the bushing. For satisfactory absorption of mechanical shock by a compressed resilient material, the resilient material should not be totally confined but should be provided with a free space or source of flow at some point such as provided in the ends of the present bushings by spaces 1. However, these spaces for reversible flow of the resilient material of the bushing may be provided in other ways. For example, in case the bushing is made co-extensive with the width of the wheel arbor hole the inner periphery of the resilient washers at the sides of the wheel may be set back from the arbor rim suiiiciently to provide the desired spaces.

The provision of a sleeve of metal or other rigid material is a particularly important feature of the present mounting. It not only provides an y accurate means of lcontrolling the amount and degree of resilience in the bushing by exertion of a 'controlled compressing force upon the resilient provides a well centered final arbor sleeve integral with the grinding wheel and makes for an ease of mounting and remounting as simple as a rigid bushed wheel and not heretofore obtained by attempted resilient mountings.

-Our resiliently bushed wheel is, then, a unit embodying the factor of resilient mounting just as it embodies all of the other essentials to satisfactory grinding. The amount of resiliency known to be most desirable for that particular size and/or type of wheel or for a certainI type of grinding 'operation is incorporated finto wheelbushing unit at the time ofinaufacture and is invention encompasses other resilient, elastic and relative rigid materials. There can also be changes in the form of the membersfrom those illustrated herein, without departing from the spirit of our invention.

What we claim is:

1. An abrasive article comprising an abrasive wheel provided with a central arbor hole and a resilient bushing mounted in the arbor hole, said bushing comprising an outer sleeve of resilient material and a strong non-resilient and rigid inner sleeve, the dimensions of the two sleeves being such that the outer sleeve is -compressively forced into intimate contact with the walls of the arbor hole by the inner sleeve whereby the bushing is frictionally retained within the wheel and provides a resilient mounting therefor.

2. An abrasive article comprising an abrasive being such that the outer sleeve is compressivelyl l forced into intimate contact with the walls of the arbor hole by the inner sleeve whereby the bushing is frictionally retained within the wheel and provides a resilient mounting therefor, the length of the bushing being less than the width of the abrasive wheel.

3. AAn abrasive article comprising an abrasive wheel provided with a central arbor hole and a resilient bushing mounted in the arbor hole, said bushing comprising an outer sleeve of resilient material and a'metal inner sleeve, the dimensions of the two sleeves being such that the outer sleeve is compressively forced into intimate contact with therefor.

the walls of the arbor hole by the inner sleeve whereby the bushing is frictionally retained within the wheel and provides 'a resilient mounting 4. An abrasive article comprising an abrasive wheel provided with a central arbor hole and a resilient bushing mounted` in the arbor hole, said bushing comprising an outer sleeve of resilient lmaterial and a strong non-resilient and rigid inner sleeve, the dimensions of the two sleeves being such that the outer sleeve is .compressively forced into intimate contact with the walls of the arbor hole by the inner sleeve whereby the bushing is frictionally retained within the wheel and provides wheel provided with a central arbor hole and a resilient bushing mounted in the arbor hole, said bushing comprising .an 4outer sleeve of resilient materiaLand a strong non-resilient and rigid inner sleeve, the dimensions of the two sleeves resilient mounting therefor, the length'of the bushing being less than the width ofthe abrasive wheel, and a pair of resilient washers positioned against the opposite side faces of said abrasive wheel and held in compressed relation thereagainst by suitable clamping means.

BOYD HQ WORK. DAVID S. KLAUDER, JR. 

